The present invention relates to a solid agricultural chemicals composition which uses a new carrier for agricultural chemicals, the preparation thereof and the method for scattering (applying) the same.
At present, agricultural chemicals formulations are divided roughly into a solid chemicals formulation and a liquid chemicals formulation from its nature, and the former includes a dust type, a dust-granule mixture type, a granule type, a wettable powder type and so forth while the latter includes an emulsifiable type, a liquid type, a suspension type and so forth. In view of way of the application, they are classified into a direct scattering (applying) type and another type which is scattered (applied) after being diluted with water or the like.
On scattering (applying) an agricultural chemicals formulation, it is preferable for the agricultural chemicals to have preparatory processes for scattering (applying) as little as possible, and to be easy for scattering (applying) in view of the workability and the like. Considering the above circumstances, a solid chemicals formulation which can be scattered (applied) directly comes to be the most preferable agricultural chemicals formulation.
As such a solid chemicals formulation which can be scattered (applied) directly without dilution, a powder type such as a dust formulation, a DL (Drift Less) powder formulation, and a flowdust formulation, and a pellet type such as a granule type formulation, a fine granule type formulation F, a micro granule type formulation, and a micro granule type formulation F are known. Except the above, a jumbo type formulation in which a powder type formulation or a granule type formulation being packed with a water-soluble film, or tablets obtained by tablet molding, are thrown from a path between rice fields into a paddy field, a smoke type formulation which is used by firing a granular type formulation or a tablet type formulation with an ignition paper, a dust type formulation, a wettable powder type formulation, or a water dispersible granule type formulation which are mixed with soil to put in a box nursery of paddy rice are known.
However, since there are a liquid type at room temperature, a solid type at room temperature and a paste form whose melting point is near a room temperature, when classified according to nature of the agrochemically active ingredient in the agricultural chemicals formulation, it has been difficult to say that a solid chemicals formulation which contains an agrochemically active ingredient in high concentration and can be easily scattered (applied) directly can be obtained by using any agrochemically active ingredient.
That is, a liquid agrochemically active ingredient at room temperature can not be made a solid chemicals formulation by itself, and it is necessary to make it into a solid state with some means. In order to make a solid or paste-like agrochemically active ingredient at room temperature to be suitable for scattering (applying) directly, it is required to be dispersed uniformly in an agricultural chemicals formulation.
Therefore, on production of a solid chemicals formulation which can be scattered (applied) directly, a liquid agrochemically active ingredient at room temperature is kept as it is or is dissolved in an appropriate solvent, and then impregnated with a suitable carrier for agricultural chemicals, or a solid or paste-like agrochemically active ingredient at room temperature is liquidized with an appropriate solvent, and then impregnated with a suitable carrier for agricultural chemicals to obtain a solid chemicals formulation.
However, when an agrochemically active ingredient in high concentration is made into a solid chemicals formulation with a method described above, the agrochemically active ingredient in the chemicals formulation may possibly be pulverized according to the storage condition or due to changes with a lapse of time, or may seep out. Accordingly methods for preventing the above disadvantages are required.
On the other hand, if an agrochemically active ingredient contained in a solid chemicals formulation is soon released from the solid chemicals formulation which can be scattered (applied) directly, the concentration of the agricultural chemicals comes to be high in the vicinity of the chemicals formulation, and phytotoxicity may arise in some cases. Therefore, it is preferable for a solid agricultural chemicals formulation to release its agrochemically active ingredient gradually from the inside of the carrier, namely having a so-called residual-effectiveness.
Further, in recent years, safety of supplementary chemicals including carriers used for agricultural chemicals especially raises a new issue, and there have been strong demands for use of supplementary chemicals which are low in toxicity such as oral toxicity, dermal toxicity, inhalation toxicity, fish-toxicity, and eye irritation, and are excellent in biodegradability, and environmentally mild.
Incidentally, as a suitable carrier for agricultural chemicals to solidify an agrochemically active ingredient, conventionally, the following materials have been known, that is, clay, talc, diatmite, bentonite, calcium carbonate, silica, pumice, vermiculite, pearlite, Attapulgite clay, and so forth as a mineral carrier, fragment of soybean powder, tobacco powder, walnut powder, wheat flour, wood powder, rice bran, wheat bran, rice hull, sawdust, pulp flock, corn stem, nut skin, and fruit core and so forth as a vegetable carrier, and further synthetic carriers made from urea, ammonium sulfate, dextrin, white carbon and so forth.
Among them, as a carrier to be expected to solve the problems such as pulverization and seeping out of the agrochemically active ingredient, white carbon is widely used in an agricultural chemicals formulation due to its excellent oil absorbency. White carbon is called amorphous silica, and is synthetic silicate which is produced by means of a wet method or a dry method, and is used as an adsorptive carrier of liquid effective ingredients, an anti-caking agent for a solid chemicals formulation using an agrochemically active ingredient having a low melting point, and an auxilliary agent for pulverization when to be pulverized.
However, since white carbon is not biodegradability, which causes an environmental problem, and easily releases an active ingredient because it is fine in powder size, the effect of providing residual-effect can not be expected.
Among other oil-absorptive carriers, diatmite and bentonite as a mineral carrier are conceivable. However diatmite has a problem of being non-biodegradability, and bentonite has a problem in such that it restrains releasing of an agrochemically active ingredient too much due to its high adsorptivity, though it has no environmental problem because it is one of the main components of soil. On the other hand, vegetable carriers are susceptible to biodegradability, but they are all low in oil absorbency and water absorbency, so that they do not solve the problem associated with solidification of liquid agrochemically active ingredients.
A variety of studies has been made about chemicals formulation to give residual-effectiveness to an agrochemically active ingredient. For instance, a method of adding an anti-oxidation agent (Japanese Patent laid-open No. Hei 3-218304), a method of enclosing an active ingredient with a photo-degradative micro-capsule (Japanese Patent laid-open No. Sho 54-109078) and a method of pelletizing a solid agrochemically active ingredient having a melting point of 50xc2x0 C. or more with amorphous silica (Japanese Patent laid-open Hei 8-143402), are known.
However, among these patent applications described above, for instance, there is apprehension of toxicity and biodegradability of the anti-oxidant in Japanese Patent laid-open of Hei 3-218304. Further, in Japanese Patent laid-open Sho 54-109078, a large amount of organic solvent is used during production, and the organic solvent is removed by drying, which causes fear on worsening of working environment during production. Still further, in Japanese Patent laid-open No. Hei 8-143402, there is only a solid agrochemically active ingredient which is effective, which means to throw out a plenty of non-biodegradability white carbon into environment. Thus, the fact is that any agricultural chemicals formulation which satisfies imparting of residual-effectiveness under consideration of safety and biodegradability of agricultural chemicals carriers to be used has not been obtained yet.
Accordingly, an object of the present invention is to provide a solid agricultural chemicals composition which is excellent in safety for environment, contains an agrochemically active ingredient in high concentration regardless of its nature, has no problem in pulverization and seeping out of the agrochemically active ingredient, and is excellent in residual-effectiveness of the agrochemically active ingredient.
As a result of assiduous study to achieve the above-described object, the present inventors have found that usage of pulverized matter of a fibre crop having suitable porosity and being excellent in oil absorbency as a carrier to carry an agrochemically active ingredient, can prevent pulverization and seeping out of the agrochemically active ingredient due to storage conditions and changes with a lapse of time, can hold a large quantity of the agrochemically active ingredient, can give less drifting of chemicals when scattered (applied) in the air, can release the agrochemically active ingredient gradually after scattering (applying) to impart residual-effectiveness, and that the fibre crop itself as a carrier disappears while undergoing biodegradability. Based upon this finding, the inventors have accomplished the present invention.
That is, the present invention is to provide a solid agricultural chemicals composition comprising a fragment of a fibre crop which is high in oil absorbency and a liquid agrochemically active ingredient at room temperature or liquid matter which is made by dissolving or dispersing an agrochemically active ingredient in a liquid solvent.
Another object of the present invention is to provide a method of producing a solid agricultural chemicals composition in which a liquid agrochemically active ingredient at room temperature or a liquid matter which is made by dissolving or dispersing an agrochemically active ingredient in a liquid solvent is impregnated into fragments of a fibre crop having high oil absorbency and water absorbency to make it into a shape of powder, pellet or tablet.
Still another object of the present invention is to provide a carrier for an oil agricultural chemicals composition which comprises fragments of a fibre crop as an active ingredient having oil absorption capacity of 100 or more.